Python | Reading .ini Configuration Files

This article aims to read configuration files written in the common .ini configuration file format. The configparser module can be used to read configuration files. Code #1 : Configuration File

Python3

abc.ini

; Sample configuration file
[installation]
library = %(prefix)s/lib
include = %(prefix)s/include
bin = %(prefix)s/bin
prefix = /usr/local

# Setting related to debug configuration
[debug]
pid-file = /tmp/spam.pid
show_warnings = False
log_errors = true
[server]
nworkers: 32
port: 8080
root = /www/root
signature:

Code #2 : Reading the file and extracting values.

Python3

from configparser import ConfigParser

configur = ConfigParser()
print (configur.read('config.ini'))

print ("Sections : ", configur.sections())
print ("Installation Library : ", configur.get('installation','library'))
print ("Log Errors debugged ? : ", configur.getboolean('debug','log_errors'))
print ("Port Server : ", configur.getint('server','port'))
print ("Worker Server : ", configur.getint('server','nworkers'))

Output :

['config.ini']
Sections : ['installation', 'debug', 'server']
Installation Library : '/usr/local/lib'
Log Errors debugged ? : True
Port Server : 8080
Worker Server : 32

One can also modify the configuration and write it back to a file using the cfg.write() method. Code #3 :

Python3

configur.set('server','port','9000')
configur.set('debug','log_errors','False')

import sys
configur.write(sys.stdout)

Output :

[installation]
library = %(prefix)s/lib
include = %(prefix)s/include
bin = %(prefix)s/bin
prefix = /usr/local

[debug]
log_errors = False
show_warnings = False

[server]
port = 9000
nworkers = 32
pid-file = /tmp/spam.pid
root = /www/root

Configuration files are well suited to specify configuration data to your program. Within each config file, values are grouped into different sections (e.g., "installation", "debug" and "server").
Each section then has a specific value for various variables in that section. For the same purpose, there are some prominent differences between a config file and using a Python source file.
First, the syntax is much more permissive and “sloppy.”

Names used in a config file are also assumed to be case-insensitive as shown in the code below -

Python3

configur.get('installation','PREFIX')

configur.get('installation','prefix')

Output :

'/usr/local'
'/usr/local'

When parsing values, methods such as getboolean() look for any reasonable value. For example, these are all equivalent.

log_errors = true
log_errors = TRUE
log_errors = Yes
log_errors = 1

The most noteworthy contrast between a config record and Python code is that, in contrast to scripts, configuration files are not executed in a top-down way. Rather, the file is read completely. On the off chance that variable substitutions are made, they are done later after the fact. For instance, it doesn't make a difference that the prefix variable is allocated after different variables that happen to utilize it.

[installation]
library = %(prefix)s/lib
include = %(prefix)s/include
bin = %(prefix)s/bin
prefix = /usr/local

Multiple configuration files can be read together and their results can be merged into a single configuration using ConfigParser, which makes it so special to use. Example - A user made their own configuration file that looks as.

; ~/.config.ini
[installation]
prefix = /Users/beazley/test
[debug]
log_errors = False

This file can be merged with the previous configuration by reading it separately Code #4 :

Python3

import os

# Previously read configuration
print (configur.get('installation', 'prefix'))

# Merge in user-specific configuration
print (configur.read(os.path.expanduser('~/.config.ini')))
print (configur.get('installation', 'prefix'))
print (configur.get('installation', 'library'))

print (configur.getboolean('debug', 'log_errors'))

Output :

'/usr/local' 
['/Users/HP/.config.ini']
'/Users/HP/test'
'/Users/HP/test/lib'
False

Python | Reading .ini Configuration Files

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